Pressure-gage.



C. R. TWITHELL.

l' PRESSURE GAGE.

APPLICATION FILED APlLBG, 1911.

1,048,287. Patented Deo. 24, 1912.

s'rnfrns ra'rnnr onirica.

CHARLES B. TWITCHELL, OF' LS ANGELES, CALIFORNIA, ASSIGNOR, BY MESNE AB- IGNMENTS, TO A. SCHRADEBS SON, INCORPORATED, OF NEW YORK,

Specification of Letters Patent.

N. Y., A con- PRESSURE-GAGE.

Patented Dec. 24, 1912.

Application lefl April 28, 1911. Serial No. 623,452.

To all whom may concern Be it' known that I, CHARLES R. Twrrcrinm., a citizen of the United States,

'residing at Los Angeles, in the county of Los Angeles and State ot' California, have invented new and useful Improvements in Pressure-Gages, of which the following is a specification.

This invention relates to pressure gages, particularly to improvements over a former patent of mine No. 927,298, dated July 6th, 1909. In my said former patent I have shown a pressure gage adapted to be applied to' the valve of a pneumatic tire for determining the pressure of air in the tire, the gage consisting of a tube with a plunger therein and a gage-bar carried by the plunger and adapted to beprojected'through the end of the ltube a distance corresponding to the distance the plunger is moved outward by the pressure of air from within the tire, the outward movement. of the plunger being resisted by a coil spring. In this former construction when the instrument was removed from the valve of the tire and the pressure relieved, the spring acted to restore the piston and gage-bar to normal retracted position, making it necessary to read the scale on the gage-har during the time that it was in extended position, and as this only happened when the instrument was held in place on the val\'e of the tire, it was more or less difficult to determine the pressure, and especially so in the dark or when the valve of the tire was at a low point.

The object of the present invention is to overcome these `disadvantages 4by providing a self-registering device whereby the selt registering device will be moved into indicating position by the piston rod and will he maintained in Suc'h indicating position after the piston and piston rod have been restored to normal position, thus making it an easy Referring to the drawings Figure 1 is 'a perspective view of the device. Fig. 2 is a longitudinal cross section, showing the piston rod and registering scale extended. Fig. 3 1s a View similar to Fig. 2, showing the piston rod, 4 the`anvil, 5 the rubber gasket washer and (3 the spring, all of which may he of any preferred form of construction.

7 designates the registering sleeve which telescopes with the end of the piston rod 3 and is slidable in the guide cap 8 on the end of the barrel 1. The sleeve 7 fits loosely over the piston rod 3, but has a frictional bearing in the guide cap 8. Thus when the piston rod 3 is moved out by the piston 2 under the air pressure, the piston rod 3 pushes out the registering sleeve 7, and after the rod 3 has been retracted by the spring (S the sleeve 7 will remain in extended posi tion by reason of its frictional contact in the guide cap 8.

The registering sleeve 7 is provided with two sets of numerals, as shown in Figs. 4 and 5; one set designatingpressure from 40 to 100 pounds per square inch. and the other set designating pressures half-way between of the members 11 produces the requisite4 friction in the guide cap 8. In order t0 prevent the registering sleeve from bein A forced entirely through the guide cap, or rom being accidentally removed manually, I forma slight projection or lip 12 near the lower end ot'y one of the members 11 which acts as a stop to strike against the guide cap 8 and limit the outward movement of the registering sleeve. If it is necessary to withdraw the sleeve entirely from the barrel, this may bf done by exerting sufficient force, as I intentionally for m the lip12 so that it will not project enough to positively prevent the 'withdrawal of the' sleeve. `Likewise the lip l2 being; @c an easy curve will permit of the egslermg sleeve being replaced Within the u after haring; been uithrlrm'n. millet Y claim isi-- j ressuregzrge, al barrel, a piston Eheren, n rod on the pieten, u spring in llre oerrel oppwlng outward movement of the piston, :L leere Leleeeopng over the end of said rml and ,ellduble within the lmrrel, said sleeve being resllenlly expzurslble to fro lonelly slide ln the barrel.

therein. .fr rod en the piston, :l Spring ln the /barrel opposing; outward movement of the v ln. e pressure frage, barrel, u piston g plson, e., sleur teeeeoping over he end or my hand at Los Angeles, Cahforma, dus

said rod amd el'uluhle within the barrel. said sleere being resllenily expausilvle to fric`A onally slide in the barrel and having :x projection formed in its lower end adapted te Strike rlle enel. of the barrel and act as a sop 'limiting outward movement of he sleeve.

3. ln e. pressure gege, a barrel, means wrhm the barrel and operatmg by zur preseure to be extended from the barrel, a sprmg;

opposg outward movement of seid means,

u regleerlng sleeve telescopng over said menus 21ml slldzxble within the barrel, a guide cap on the end of lhe barrel in Which said sleeve slidably fits, said sleeve being formed from e single sheet metal strip, the Strip beng'doublefl on itself and the two members lrereo curved laterally lo form Substantially semiCylindrical members, each of said members being provided with a set of indieating numerals.

lx1 tesmonjv whereof, I have hereunto set l'h day of April, 1911.

CHARLES R. TWTCHELL.

In presence 01'?- G. T. llAoKLEY. FRANK, L. GRAHAM. 

